Many bedridden patients cannot turn over in bed and have blood circulation disorders with the risk of developing pressure ulcers (also called “bed sores”). Pressure ulcers deteriorate the health status of patients sometimes crucially. To avoid this problem, home caregivers need to help to change patients posture about every two hours, which is a heavy burden for the home caregivers.
Meanwhile, in today's stressful society, more and more people are unconsciously suffering from sleep disorders such as sleep apnea syndrome, snoring, and teeth grinding. A severe form of sleep apnea syndrome is a life-threatening disease, and even a milder form of it reduces the quality of sleep, possibly causing affected people to fall asleep on duty. For example, if pilots and drivers of trains and buses are affected with sleep disorders, they may cause a catastrophic accident involving human lives. For these people to lead a normal social life, it has been hoped to develop measures for easily preventing or reducing sleep disorders of which people are unaware themselves, such as sleep apnea syndrome, snoring, and teeth grinding.
Patent Literatures 1 and 2 have proposed care bed techniques which help a patient to change his/her posture in bed. In Patent Literature 1, the bed is automatically rotated along the circumference of a circular slider so as to turn over a patient in bed.
In Patent Literature 2, the bed includes a bottom board having a lower surface from which a semicircular body protrudes so as to form a semicircular orbit in the width direction of the bed; and a bed frame which holds the bottom board in a tiltable manner while supporting the semicircular body so as to rotate it in a half circle along its circumference. When the bottom board is driven, the semicircular body rotates in a half circle along the semicircular orbit, allowing a bottom surface of the bottom board to tilt in the width direction of the bed.